1. Field of the Invention
The present general inventive concept relates to a turbo fan for an air conditioner, and more particularly, to a turbo fan which comprises blades adapted to reduce noise.
2. Description of the Related Art
Generally, a blowing fan is used as a means of transferring air by virtue of a rotational force of a rotor or blades, and is mounted in a refrigerator, an air conditioner, a vacuum cleaner, etc.
In particular, the blowing fan is classified into an axial flow fan, a sirocco fan, a turbo fan, etc. according to a manner of suctioning or discharging air or the shape of the blowing fan. The turbo fan is a blowing fan which sucks air in an axial direction of the turbo fan, and discharges the air radially through spaces between blades, that is, through a lateral side of the turbo fan.
The turbo fan does not require a duct, and can be applied to a relatively large product, since it is adapted to allow air to be naturally induced into the fan and then discharged from the fan to the outside of the fan.
FIG. 1 is a cross-sectional view illustrating an air conditioner having a conventional turbo fan, FIG. 2 is a perspective view illustrating a structure of the conventional turbo fan, and FIG. 3 is a perspective view illustrating a structure of a conventional turbo fan different from that illustrated in FIG. 2.
Referring to FIG. 1, an air conditioner includes a cabinet 1 defining an appearance of the air conditioner and being embedded in a ceiling, a turbo fan 10 positioned within the cabinet 1, a fan motor 2 connected to the turbo fan 10, and a heat exchanger 3 around a discharge part of the turbo fan 10.
The cabinet 1 includes a suction port 1a to suck air in a room, and a discharge port 1b to discharge conditioned air into the room.
Referring to FIG. 2, the turbo fan 10 of FIG. 1 includes a main plate 11 having a hub 11a coupled to a rotational shaft of the fan motor 2 of FIG. 1, a plurality of blades 12 arranged radially at predetermined intervals on an outer periphery of the main plate 11 while being coupled perpendicularly to the main plate 11, and a shroud 13 coupled in a ring shape to the blades 12 along one end of each blade 12.
The turbo fan 10 is formed at a front side thereof with a suction port 14, and at a lateral side thereof with discharge ports 15 such that, when the turbo fan 10 is rotated by a driving force of the fan motor 2, external air is sucked into the turbo fan 10 through the suction port 14 defined inside the shroud 13 via a suctioning force, and then flows towards the discharge ports 15 along pathways between the blades 12.
Such a conventional turbo fan 10 is assembled through a post-machining process, such as thermal bonding, after previously forming the main plate 11 and the plurality of blades 12 with a single mold, and forming the shroud 13 with a different mold.
When the turbo fan 10 is made through such a post-machining process, outer ends 12a of the respective blades 12 are coupled to the main plate 11, thereby providing an advantageous effect in air flow. However, such a method for producing the conventional turbo fan increases the number of assembling operations, the number of molds, and production times.
In order to solve the problems as described above, a turbo fan 20 illustrated in FIG. 3 is formed by integrally molding a main plate 21, blades 22, and a shroud 23 with a single mold.
In order to adopt such a molding method, an outer diameter of the main plate 21 is smaller than or equal to an inner diameter of the shroud 23 such that the turbo fan 20 can be easily taken out of the mold. When the turbo fan 20 is made according to this method, the number of assembling operations and the number of molds are decreased, thereby lowering manufacturing costs. However, with this method, since outer low ends 22a of respective blades 22 are exposed to the outside of the turbo fan, the turbo fan is more likely to generate turbulence at a predetermined portion of the blades 22 upon rotation of the turbo fan 20 in comparison to the conventional turbo fan 10 illustrated in FIG. 2. Specifically, turbulence may be generated at the outer low end 22a of each blade 22.
Such turbulence deteriorates air flow through the pathways, causing noise.